update header.html
update other html template which import header
footer html template update
api-index brand page update
changelog docs page update
index changelog page update
update header.html
add header_start.html
update header.html
update other page
merge master
Merge remote-tracking branch 'qiniu/master' into html_template_update

Conflicts:
	_layouts/changelog.html
css update for style
Merge pull request #113 from SunLn/html_template_update

html template update